Deep Gorgonians and Corals of the Mediterranean Sea

Recent studies, carried out by means of innovative technological tools as remotely operated vehicles (ROVs), have highlighted the richness of the Mediterranean deep‐sea environments, characterized by great diversity and abundance of organisms. In particular, corals, gorgonians, and sponges play the important ecological role of ecosystem engineers in deep marine environments, creating complex three‐dimensional habitats enhancing high biodiversity and ecosystem functioning at every level. Coral forests and bathyal white coral communities, starting from depths of 50–70 m and below 300 m, respectively, represent the richest ecosystems known so far for the Mediterranean basin. The different assemblages show a strong heterogeneity, varying in terms of specific composition, abundance, size of colonies, and associated fauna, even on a small spatial scale. Unfortunately, the high commercial fishing effort of trawling and longline fleets mainly operating along this bathymetric range represents a major threat for these vulnerable marine ecosystems, particularly in consideration of their structuring organisms which are long‐lived species with slow growth rates and recovery ability. Further knowledge on deep coral assemblages is urgently needed to implement effective management and proper conservation measures. This approach is now an international priority that proceeds together with the inclusion of the structuring species in numerous directives

Impacts of Marine Litter on Mediterranean Reef Systems: From Shallow to Deep Waters

n/

Serum amino acid profiles in normal subjects and in patients with or at risk of Alzheimer dementia

Background/Aims: Abnormalities in the plasma amino acid profile have been reported in Alzheimer disease (AD), but no data exist for the prodromal phase characterized by subjective memory complaint (SMC). It was our aim to understand if serum amino acid levels change along the continuum from normal to AD, and to identify possible diagnostic biomarkers. Methods: Serum levels of 15 amino acids and 2 organic acids were determined in 4 groups of participants – 29 with probable AD, 18 with mild cognitive impairment (MCI), 24 with SMC, and 46 cognitively healthy subjects (HS) – by electrospray tandem mass spectrometry. Results: Glutamate, aspartate, and phenylalanine progressively decreased, while citrulline, argi­ninosuccinate, and homocitrulline progressively increased, from HS over SMC and MCI to AD. The panel including these 6 amino acids and 4 ratios (glutamate/citrulline, citrulline/phenylalanine, leucine plus isoleucine/phenylalanine, and arginine/phenylalanine) discriminated AD from HS with about 96% accuracy. Other panels including 20 biomarkers discriminated SMC or MCI from AD or HS with an accuracy ranging from 88 to 75%. Conclusion: Amino acids contribute to a characteristic metabotype during the progression of AD along the continuum from health to frank dementia, and their monitoring in elderly individuals might help to detect at-risk subjects

Deep Coral Oases in the South Tyrrhenian Sea

A Mediterranean \u2018\u2018roche du large\u2019\u2019 ecosystem, represented by four rocky shoals, located a few miles apart on a muddy bottom at 70\u2013130 m depth in the gulf of St. Eufemia (Calabria, South Tyrrhenian Sea), was studied by means of Remotely Operated Vehicle (ROV) photo imaging. The shoals host highly diversified coral communities, mainly composed of arborescent colonies of gorgonians (Callogorgia verticillata, Paramuricea clavata, Paramuricea macrospina, Bebryce mollis, Villogorgia bebrycoides, Corallium rubrum, and Leptogorgia sarmentosa), and antipatharians (Antipathella subpinnata, Antipathes dichotoma and Parantipathes larix). The coral colonies reach high densities (up to ca. 17 colonies m22) and large sizes, such as the over 1.5 m wide antipatharian colonies. We hypothesized that the abundance and composition of the coral assemblages differed significantly among the rocky shoals and with respect to the surrounding soft bottoms. Various environmental variables were tested as possible explanatory factors of the observed differences. Moreover, due to their offcoast localization, we report here that these unique ecosystems are potentially subjected to a strong pressure from the local fishing activities, which were tentatively characterized. The recorded coral b-diversity among the shoals supports the hypothesis that these habitats behave like small oases of hard substrata interspersed in a muddy bottom. Because of their intrinsic beauty and rarity and their biological and ecological value, we stress the need of specific actions aimed at the urgent protection of these oases of biodiversity

Role of deep sponge grounds in the Mediterranean Sea: a case study in southern Italy.

Abstract The Mediterranean spongofauna is relatively well-known for habitats shallower than 100 m, but, differently from oceanic basins, information upon diversity and functional role of sponge grounds inhabiting deep environments is much more fragmentary. Aims of this article are to characterize through ROV image analysis the population structure of the sponge assemblages found in two deep habitats of the Mediterranean Sea and to test their structuring role, mainly focusing on the demosponges Pachastrella monilifera Schmidt, 1868 and Poecillastra compressa (Bowerbank, 1866). In both study sites, the two target sponge species constitute a mixed assemblage. In the Amendolara Bank (Ionian Sea), where P. compressa is the most abundant species, sponges extend on a peculiar tabular bedrock between 120 and 180 m depth with an average total abundance of 7.3 \ub1 1.1 specimens m-2 (approximately 230 gWW m-2 of biomass). In contrast, the deeper assemblage of Bari Canyon (average total abundance 10.0 \ub1 0.7 specimens m-2, approximately 315 gWW m-2 of biomass), located in the southwestern Adriatic Sea between 380 and 500 m depth, is dominated by P. monilifera mixed with living colonies of the scleractinian Madrepora oculata Linnaeus, 1758, the latter showing a total biomass comparable to that of sponges (386 gWW m-2). Due to their erect growth habit, these sponges contribute to create complex three-dimensional habitats in otherwise homogenous environments exposed to high sedimentation rates and attract numerous species of mobile invertebrates (mainly echinoderms) and fish. Sponges themselves may represent a secondary substrate for a specialized associated fauna, such zoanthids. As demonstrated in oceanic environments sponge beds support also in the Mediterranean Sea locally rich biodiversity levels. Sponges emerge also as important elements of benthic\u2013pelagic coupling in these deep habitats. In fact, while exploiting the suspended organic matter, about 20% of the Bari sponge assemblage is also severely affected by cidarid sea urchin grazing, responsible to cause visible damages to the sponge tissues (an average of 12.1 \ub1 1.8 gWWof individual biomass removed by grazing). Hence, in deep-sea ecosystems, not only the coral habitats, but also the grounds of massive sponges represent important biodiversity reservoirs and contribute to the trophic recycling of organic matter

Deep Aggregations of the Polychaete <i>Amage adspersa</i> (Grube, 1863) in the Ionian Sea (Central Mediterranean Sea) as Revealed via ROV Observations

Many sessile and tube-dwelling polychaetes can act as ecosystem engineers, influencing the physical–chemical and biological characteristics of their habitats, increasing structural complexity. Thus, they are considered structuring species. In summer of 2021, in southern Sicily (Ionian Sea), benthic assemblages dominated by Ampharetidae Amage adspersa were discovered via an ROV survey at a depth range between 166 and 236 m on muddy horizontal seafloor. Large aggregations of this species (up to 297.2 tubes m−2), whose tubes are formed from Posidonia oceanica debris, occurred alternately with tube-free areas. The area was characterized by the sporadic presence of vulnerable sea pens Funiculina quadrangularis (up to 0.08 col. m−2) and Virgularia mirabilis (up to 0.16 col. m−2), and it was possible to detect signs of trawling as well the presence of marine litter (up to 24.0 items 100 m−2). The habitat description, distribution, and density of the tubes of A. adspersa were assessed via imaging analysis. In addition, morphological diagnostic analyses were carried out on some sampled specimens and on their tubes. The acquired data shed new light on how polychaetes can exploit the dead tissues of P. oceanica, contributing to highlight interactions between benthic fauna and seagrass detritus in the marine environment and their ecological role in enhancing the spatial heterogeneity of soft areas of the Mediterranean seafloor

The coral assemblages of an off-shore deep Mediterranean rocky bank (NW Sicily, Italy)

In this study we characterized the deep assemblages dwelling at 200\u2013250 m depth on a large shoal off Capo St. Vito Promontory (Northwestern coast of Sicily, South Tyrrhenian Sea) by means of ROV-imaging. Two assemblages of suspension feeders, dominated by the gorgonian Callogorgia verticillata and by the black coral Leiopathes glaberrima, together with a tanatocoenosis of the colonial yellow scleractinian coral Dendrophyllia cornigera, were examined. The three main species were significatively distributed into two areas corresponding to different habitat preferences: a more elevated hardground hosting black corals and a gently sloping, silted rocky bottom hosting the other coral species. The study area is subjected to a heavy pressure from the professional fishery, resulting in the mechanical damage of numerous colonies, some of which are then overgrown by various epibionts including a parasitic bioluminescent zoanthid, new for the Mediterranean fauna, and tentatively identified as Isozoanthus primoidus. In the Mediterranean Sea, these deep off-shore rocky banks are widely known among recreational and professional fishermen due to their rich fish fauna. However, there has been still little effort into quantifying and characterizing the extent of the impact and its consequences on the benthic communities, which may represent, as in this case, only a partial picture of their original structure and extent